#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void foo (char *buf, int num)
{
  while (num--)
    strcat (buf, "f");
}

int main()
{
  srand (getpid ());
  while (1)
    {
      int num = rand () % 1024;
      char *buf = malloc(num);
      foo (buf, num);
      printf ("%d, %p, %s\n", num, buf, buf);
      free (buf);
    }
}